Why when i try to turn on my camera, lady's camera is off?

This issue can be occured due the fact that you are using Live chat instead of private chat.

 

Live chat does not have feature to use two camera's (yours and lady's) at same time. 
For this you need to use private chat. 

For more useful information  about this service read article:
https://www.bridge-of-love.com/article-live_chat_private_chat-51.html